The present invention relates generally to sealing O-rings, and more particularly, to consumable O-rings used to create vacuum tight seals between transport modules and other interfacing modules.
Transport modules are generally used in conjunction with a variety of substrate processing modules, which may include semiconductor etching systems, material deposition systems, and flat panel display etching systems. Due to the growing demands for cleanliness and high processing precision, there has been a growing need to reduce the amount of human interaction between processing steps. This need has been partially met with the implementation of transport modules which operate as an intermediate handling apparatus (typically maintained at a reduced pressure, e.g., vacuum conditions). By way of example, a transport module may be physically located between one or more clean room storage facilities where substrates are stored, and multiple substrate processing modules where substrates are actually processed, e.g., etched or have deposition performed thereon.
In this manner, when a substrate is required for processing, a robot arm located within the transport module may be employed to retrieve a selected substrate from storage and place it into one of the multiple processing modules. As is well known to those skilled in the art, the use of a transport module to "transport" substrates among multiple storage facilities and processing modules is typically referred to as a "cluster tool architecture."
FIG. 1 depicts a typical cluster tool architecture 100 illustrating the various chambers that interface with a transport module 106. Transport module 106 is shown coupled to three processing modules 108a-108c which may be individually optimized to perform various fabrication processes. By way of example, processing modules 108a-108c may be implemented to perform transformer coupled plasma (TCP) substrate etching, layer depositions, and sputtering. Connected to transport module 106 may a load lock 104 that is implemented to provide substrates to transport module 106.
As illustrated, load lock 104 is coupled to a clean room 102 where substrates may be stored. In addition to being a retrieving and serving mechanism, load lock 104 may also serve as a pressure varying interface between transport module 106 and clean room 102. Therefore, transport module 106 may be kept at a constant pressure (e.g., vacuum), while clean room 102 is kept at atmospheric pressure. However, in order to prevent leakage between modules during pressure varying transitions, various types of O-rings are implemented.
As is well known in the art, conventional O-rings are employed between chambers to assure that vacuum conditions are maintained during a substrate transfer between transport module 106 and processing modules 108a-108c are exposed to various corrosive gas chemistries. Consequently, these O-rings must be replaced periodically in order to maintain proper processing conditions. Unfortunately, the replacement of these types of O-rings may be a time consuming and laborious proposition.
To facilitate the discussion of the problems associated with prior art O-ring replacement methods, FIG. 2 provides a three dimensional perspective of a conventional interfacing arrangement 200 having a valve body 205 positioned between a processing module 108 and a transport module 106. As shown, valve body 205 has a valve drive assembly 206 positioned below valve body 205. Further, valve body 205 may include two interface ports 216 which provide a passage way for substrates to be transported in and out of processing module 108. In addition, valve drive assembly 206 generally includes a number of mechanical interconnections, electrical connections and gas conduit networks designed to raise and lower a shaft 208 which is connected to a gate plate 210.
Shaft 208 and its associated components are discussed in greater detail in U.S. patent application Ser. No. 08/679,357 filed on the same day as the instant application, naming Trace L. Boyd and Martin F. Yeoman as inventors, and entitled "Vacuum Chamber Gate Valve and Method for Making Same." This application is hereby incorporated by reference.
To establish vacuum tight seals between facets 212 of processing module 108 and transport module 106, O-rings 220 may be sandwiched between processing module 108 and transport module 106. Typically, the modules are bolted together, pneumatics (e.g., air supply lines) and gas lines are connected and tested, electrical connections are connected and tested, and computer connections are made to various testing computers running testing software. Thus, when the time comes to replace worn out O-rings 220, transport module 106, processing module 108 and associated connections must be disconnected and then reconnected. In addition to being time consuming, the dismantled procedure generally requires highly trained personnel knowledgeable in the technology. Consequently, the O-ring replacement process typically tends to be expensive, and requires long, periods of down time which unfortunately translates into reduced overall throughput.
A further disadvantage associated with the lengthy and costly process of dismantling entire cluster architectures is the risk of generating misalignments of processing module 108 and transport module 106, and warping to valve body 205. By way of example, in order to replace O-ring 221, drive assembly 206 must be removed from valve body 205 by removing a bonnet plate 222, and then disassembling all of the accompanying mechanical interconnections and electrical contacts located inside of valve body 205 and drive assembly 206. Once these items are removed, the structural integrity of valve body 205 tends to be weaker without the internal support.
Consequently, the more frequently O-rings 220 are replaced due to their interaction with the corrosive gas chemistries, the greater the possibility that irreparable warping will be introduced. When this happens, the entire valve body may have to be replaced or faced-off to cure the resulting warping since basic O-ring replacement will not be sufficient to maintain a proper seal.
In view of the forgoing, what is needed is a method for efficiently replacing consumable O-rings between interfacing chambers without having to disassemble entire sections of a cluster architecture. In addition, it would be desirable to replace consumable O-rings rapidly and cost effectively without introducing extended down times which inefficiently reduce throughput.